WASHINGTON – Vice President Joe Biden, at a fund-raiser in Washington Tuesday night for US Representative Edward J. Markey, was highly critical of the Republican Party, even as he praised Markey and implored supporters not to take the Massachusetts election for granted.

“Ed Markey in the Senate is not a single vote; Ed Markey in the Senate is part of a movement,” Biden said at an event that raised $250,000 for Markey’s campaign. “Ed Markey in the Senate will command respect and attention the moment he stands on the floor to speak for the first time.”

The fund-raiser, held at a private home in an expensive neighborhood in Washington, was also headlined by former vice president Al Gore and Victoria Reggie Kennedy, the widow of the late US senator Edward M. Kennedy.

Biden urged some 200 attendees not to assume that Markey will win, saying that “this is a strange moment” and that, without the president at the top of the ticket, turnout by minority-group voters in Massachusetts might be low.

“There’s a big difference in this race,” Biden said. “Barack Obama’s not at the head of the ticket. And that means those legions of African-Americans and Latinos are not automatically going to come out. No one has energized them like Barack Obama. But he’s not on the ticket, so don’t take this one for granted.”

Biden repeatedly praised Markey, saying “few have the quality of character and intellect and emotional IQ that Ed Markey has.”

He saved some of his most biting rhetoric for the Republican Party.

“It’s a pretty simple proposition: The United States of America, and the state of Massachusetts, does not need another Republican in the Senate,” Biden said. “I’m being straight about this. This is not your father’s Republican Party.”

“They’re not bad guys. They don’t get it!” Biden added at another point. “But Ed does. In his gut, Ed gets it.”

Biden was harshest when referring to two new Tea Party-backed senators, Rand Paul of Kentucky and Ted Cruz of Texas. “Think about this,” he said. “Have you ever seen a time when two freshman senators are able to cower the bulk of the Republican Party in the Senate? That is not hyperbole.”

“I actually said: ‘Are you kidding? These are two freshman,’ ” Biden added. “This is a different, party, folks.”

Markey was not there – he was debating Republican opponent Gabriel E. Gomez in Springfield – but Markey’s wife, Susan Blumenthal, did attend.